Rock burst process of limestone and its acoustic emission characteristics under true-triaxial unloading conditions
Rock burst process of limestone and its acoustic emission characteristics under true-triaxial unloading conditions
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DOI：
10.1016/j.ijrmms.2009.09.003
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发表时间：
2010-02-01
影响因子：
7.2
通讯作者：
Feng, J. L.
中科院分区：
文献类型：
--
作者：
He, M. C.;Miao, J. L.;Feng, J. L.
岩石破坏过程与声发射（AE）有关。因此，可以利用声发射监测技术研究实验室中不同应力路径下诸如岩爆等剧烈的岩石破坏过程。本文对取自中国嘉禾煤矿1140米深处岩芯块体的古生代海相沉积石灰岩样品进行了真三轴条件下的单面动态卸载试验。对全波声发射数据进行了频谱分析，得到了显示岩爆阶段声发射信号频率 - 振幅关系的图表。总结了试验条件下石灰岩的动态损伤过程和特征。通过对声发射信号的快速傅里叶变换（FFT）分析发现，样品存在两个主要频率范围，即较低（60 - 100 kHz）和较高（170 - 190 kHz）。当石灰岩样品处于相对较低应力时，声发射信号具有高频低幅的特征。随着应力增加，声发射信号往往更倾向于高幅特征。在岩石样品发生破裂破坏附近，观察到有更高振幅和更低频率的事件。从岩石样品卸载状态到其破坏，声发射累积能量释放迅速增加。动态卸载试验装置为深入了解岩爆特征提供了一种有用的工具。（C）2009爱思唯尔有限公司。保留所有权利。
The rock failure process is associated with acoustic emission (AE). Hence, violent rock failure processes such as rock burst under different stress paths in laboratory can be studied using the AE monitoring technique. In this paper, single-face dynamic unloading tests under true-triaxial condition were carried out for Paleozonic marine sedimentation limestone samples produced by blocks cored from 1140 m depth in Jiahe coal mine of China. Frequency-spectra analysis was conducted for the full-wave AE data and figures showing the relationship of frequency-amplitude of AE signals in rock burst stages were obtained. The dynamical damage process and characteristics of limestone under the test condition are summarized. It is found from the fast Fourier transformation (FFT) analysis of the AE signals that there exist two main frequency ranges, i.e. lower (60-100 kHz), and higher (170-190 kHz), for the samples. When the limestone samples are under relatively lower stress, the AE signals are characterized by high frequency and low amplitude. As the stress increases, the AE signals tend to shift more towards a signature of high amplitude. Near the bursting failure of the rock samples, it is observed that there are much higher amplitude and lower frequency events. The AE accumulated energy release rapidly increases from the unloading state of the rock samples to its failure. The dynamic unloading test facility provides a useful tool to gain an insight into the characteristics of rock bursts. (C) 2009 Elsevier Ltd. All rights reserved.